...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of bacteriology >Uniport of anionic citrate and proton consumption in citrate metabolism generates a proton motive force in Leuconostoc oenos.
【24h】

Uniport of anionic citrate and proton consumption in citrate metabolism generates a proton motive force in Leuconostoc oenos.

机译：柠檬酸根阴离子的单口运输和柠檬酸根代谢中质子的消耗会在Leuconostoc oenos中产生质子动力。

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The mechanism and energetics of citrate transport in Leuconostoc oenos were investigated. Resting cells of L. oenos generate both a membrane potential (delta psi) and a pH gradient (delta pH) upon addition of citrate. After a lag time, the internal alkalinization is followed by a continuous alkalinization of the external medium, demonstrating the involvement of proton-consuming reactions in the metabolic breakdown of citrate. Membrane vesicles of L. oenos were prepared and fused to liposomes containing cytochrome c oxidase to study the mechanism of citrate transport. Citrate uptake in the hybrid membranes is inhibited by a membrane potential of physiological polarity, inside negative, and driven by an inverted membrane potential, inside positive. A pH gradient, inside alkaline, leads to the accumulation of citrate inside the membrane vesicles. Kinetic analysis of delta pH-driven citrate uptake over a range of external pHs suggests that the monovalent anionic species (H2cit-) is the transported particle. Together, the data show that the transport of citrate is an electrogenic process in which H2cit- is translocated across the membrane via a uniport mechanism. Homologous exchange (citrate/citrate) was observed, but no evidence for a heterologous antiport mechanism involving products of citrate metabolism (e.g., acetate and pyruvate) was found. It is concluded that the generation of metabolic energy by citrate utilization in L. oenos is a direct consequence of the uptake of the negatively charged citrate anion, yielding a membrane potential, and from H(+)-consuming reactions involved in subsequent citrate metabolism, yielding a pH gradient. The uptake of citrate is driven by its own concentration gradient, which is maintained by efficient metabolic breakdown (metabolic pull).
机译：研究了柠檬酸芥中柠檬酸盐转运的机理和能量学。添加柠檬酸时，L。oenos的静息细胞会产生膜电位（δpsi）和pH梯度（δpH）。在滞后时间之后，内部碱化之后是外部介质的连续碱化，表明质子消耗反应参与了柠檬酸盐的代谢分解。制备L.oenos的膜囊泡，并将其融合到含有细胞色素C氧化酶的脂质体上，以研究柠檬酸盐转运的机制。杂合膜中柠檬酸盐的吸收受到负性内的生理极性膜电位的抑制，而受正性内膜电位反转的驱动。碱性条件下的pH梯度会导致柠檬酸在膜囊泡内积累。在一系列外部pH值上pH值驱动柠檬酸摄取的动力学分析表明，单价阴离子物质（H2cit-）是转运的颗粒。总之，数据表明柠檬酸的转运是一个电生成过程，其中H2cit-通过单向机制跨膜转运。观察到同源交换（柠檬酸盐/柠檬酸盐），但是没有发现涉及柠檬酸盐代谢产物（例如乙酸盐和丙酮酸盐）的异源反端口机制的证据。得出的结论是，柠檬酸利用柠檬色葡萄球菌产生的代谢能是摄取带负电荷的柠檬酸根阴离子，产生膜电位的直接结果，并且是后续柠檬酸根代谢所涉及的消耗H（+）的反应的直接结果，产生pH梯度。柠檬酸盐的吸收是由其自身的浓度梯度驱动的，该浓度梯度通过有效的代谢分解（代谢代谢）得以维持。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号